Go already! It is a composite interjection (go now) whose meaning is expressed, above all, disdain, disbelief to what was said by a third party in a conversation. Depending on context, it also has a semantic value of surprise. You can enter between signs of admiration or exclamation point to give greater enhancement, as here presented
* Only one "like" per meaning and day, the more "likes" the meaning will appear higher in the list
